Autor: Ranachowski, P. - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: Mechanical-acoustic method used to estimate porcelain materials degradation
Mechaniczno-akustyczna metoda badań degradacji tworzyw porcelanowych
Autorzy:: Ranachowski, Z.
Rejmund, F.
Ranachowski, P.
Tematy:: degradacja tworzyw porcelanowych
badania emisji akustyczne
naprężenia ściskające
porcelain materials degradation
acoustic emission measurements
compressive stress; Pokaż więcej
Wydawca:: Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Powiązania:: https://bibliotekanauki.pl/articles/153185.pdf Link otwiera się w nowym oknie
Opis:: This paper presents the results of acoustic emission (AE) measurements of samples under slowly increasing compressive stress. Additional research, concerning structure and parameters of the material, was performed using microscopic method. The objects of investigation were samples of porcelain material C 120 and C 130 types. These aluminous porcelains find wide application in modern electrotechnical engineering. The aim of study was recognition of stages of degradation processes of the porcelain structure. The analysis of mechanical-acoustic characteristics pointed out diversified strength and complicated mechanism of material degradation. The effectiveness of structural reinforcement of aluminous porcelains was ascertained. On the basis of AE measurements of compressed samples the successive stages of structure degradation have been distinguished. Detailed microscopic analysis enabled to specify the processes of the gradual growth of microcracks and decohesion of the ceramic body.
W pracy przedstawiono wyniki badań emisji akustycznej (EA) próbek poddanych wolno narastającemu naprężeniu ściskającemu. Uzupełniające badania strukturalne wykonane zostały metodą mikroskopii optycznej. Przedmiotem badań były próbki tworzyw porcelanowych rodzaju C 120 i C 130. Najważniejszym celem pracy było rozpoznanie etapów degradacji struktury tworzyw. Badania wykazały znaczne zróżnicowanie wytrzymałości próbek oraz złożony, kilkuetapowy mechanizm degradacji struktury porcelany. Opisane etapy niszczenia struktury próbek znajdują odniesienie w wieloletnich procesach starzeniowych tworzywa izolatorów w eksploatacji. Zastosowana mechaniczno-akustyczna metoda pozwoliła na wyróżnienie poszczególnych etapów degradacji badanych struktur. Udokumentowano proces powstawania, rozwoju i łączenia się pęknięć, które stopniowo doprowadzają do zniszczenia badanych próbek.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Acoustic emission probes of foam drainage processes in H2O-C2H5OH-air system with content of detergent triton X-100
Autorzy:: Rzeszotarska, J.
Rejmund, F.
Ranachowski, P.
Wydawca:: Polskie Towarzystwo Akustyczne
Powiązania:: https://bibliotekanauki.pl/articles/332741.pdf Link otwiera się w nowym oknie
Opis:: The acoustic emission (AE) of short-lived static foams from non-ionic detergent Triton X-100 in ethanol-water solutions has been investigated. The AE of foam drainage process has shown two different stages of behaviour. The first step up to 80 s was without the appearance of AE signals. During this stage the rearrangement of bubbles has been observed. The next, main stage of drainage process proceeded with a high intensity AE generation. The results suggest that the AE technique gives the direct possibility of foam stability measurement.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Microstructure and Degree of Degradation of ZnO Varistors in Surge Arresters Due to Operation
Autorzy:: Papliński, P.
Wańkowicz, J.
Ranachowski, P.
Ranachowski, Z.
Tematy:: surge arrester
MO varistor
microstructure of ceramics
ceramic material degradation; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/356415.pdf Link otwiera się w nowym oknie
Opis:: The paper presents the test results for the microstructure of ZnO varistors comprising high voltage gapless surge arresters. The tests were performed on varistors produced in different periods and by various manufacturers. The research was inspired by different characteristics of changes in values of current flowing through surge arresters as a function of changes in values of system voltage in a 220 kV substation, and the temperature in a multi-year cycle. Furthermore, the effects of varistor microstructure degradation following a failure of an unsealed surge arrester were investigated. The results provided the grounds for assessment of ZnO varistor microstructure parameters in terms of their durability and resistance to degradation processes.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Investigation of Microstructure of ZnO Varistors Taken From Surge Arrester Counters
Autorzy:: Papliński, P.
Wańkowicz, J.
Ranachowski, P.
Ranachowski, Z.
Tematy:: surge arrester counter
ZnO varistors
microstructure of ceramics
ceramic material degradation; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/355223.pdf Link otwiera się w nowym oknie
Opis:: The paper presents investigations of microstructure of varistors of damaged surge arrester counters. A similar ZnO varistor, not subjected before to operation, was a point of reference in this research. The results of investigations of the ZnO varistors show an untypical phase composition of their material, which was characterized by unsatisfying homogeneity and cohesion. The degradation processes of varistor material in the subsequent stages were recognized and described. A harmful impact of humidity inside the untight surge arrester counter on its operation and its ZnO varistors was proved. Some conclusions being the result of the operation checking of surge arrester counters were presented too.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Examination of the Properties of Samples from Glass-Epoxy Core Rods for Composite Insulators Subjected to DC High Voltage
Autorzy:: Wieczorek, K.
Jaroszewski, M.
Ranachowski, P.
Ranachowski, Z.
Tematy:: DC high voltage
composite insulator
glass-epoxy core
dielectric spectroscopy
Raman spectroscopy; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/351254.pdf Link otwiera się w nowym oknie
Opis:: This article presents the results of an examination performed on a set of samples of glass-epoxy core rods used in composite insulators with silicone rubber housings. The goal of the examination was to test the aging resistance of the core material when exposed to Direct Current (DC) high voltage. Long term exposure of a glass-epoxy core rod to DC high voltage may lead to the gradual degradation of its mechanical properties due to the ion migrations. Electrolysis of the core material (glass fiber) may cause electrical breakdown of the insulators and consequently lead to a major failure. After being aged for 6000 hours under DC high voltage, the samples were subjected to microscopic analysis. Their chemical composition was also examined using Raman spectroscopy and their dielectric losses and conductance in the broad range of frequencies were tested using dielectric spectroscopy.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Acoustic examination of epoxy-glass insulator material
Autorzy:: Ranachowski, P.
Ranachowski, Z.
Rejmund, F.
Stankiewicz, J.
Tematy:: composite insulator
epoxy-glass material
nondestructive ultrasonic measurements
acoustic emission; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/176877.pdf Link otwiera się w nowym oknie
Opis:: Ultrasonic, microscopic and acoustic emission (AE) methods were applied to investigate the microstructure of composite rods, used as a carrying element of the medium voltage insulators. Such features of material structure as homogeneity level and the appearance of defects were discussed. The research was aimed at determining the influence of the technology of epoxy-glass fabrication on quality parameters of the insulator rods. The results of acoustic testing were compared with the effects of microscopic investigation.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Aluminous porcelain degradation study using mechanoacoustic and microscopic methods
Autorzy:: Ranachowski, P.
Rejmund, F.
Ranachowski, Z.
Pawełek, A.
Piątkowski, A.
Tematy:: porcelana
izolator ceramiczny
emisja akustyczna
analiza mikroskopowa
degradacja struktury
aluminous porcelain
ceramic insulators
insulator testing
acoustic emission
microscopic analysis
structural degradation; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/140868.pdf Link otwiera się w nowym oknie
Opis:: This experimental paper comprises the results of acoustic emission (AE), microscopic and ultrasonic measurements of samples subjected to slowly increasing compressive stress. On the basis of conducted measurements the successive stages of the material structural degradation have been recognized. The objects of study were samples made of C 120 aluminous porcelain. The investigated material has found at present the application in the fabrication of technical elements like overhead power line insulators. In the case of such objects, not only high mechanical strength, but especially elevated durability as well as operational reliability are required. The expected "life time" of net insulators during exploitation is about 40 years. The analysis of obtained mechanoacoustic dependences pointed out a complex mechanism of degradation of the material. Microscopic investigation of samples, which were stressed to different levels of load, enabled to specify the development of gradual growth of microcracks and successive crushing out of elements of the structure. These processes appear to be similar to the ageing processes occurring in the material during long period of exploitation under a working load. Three stages of the structure degradation were distinguished. The preliminary and subcritical ones show low or moderate intensity of AE signals and considerable variety for the particular samples. The critical stage directly precedes the destructtion of samples. Its range is relatively narrow and reveals the AE activity of high energy. The effectiveness of dispersive and fibrous reinforcement of modern aluminous porcelain C 120 type has been described. Structural strengthening by corundum grains and mullite needle shaped crystals improves mechanical parameters and distinguishes this material from typical aluminosilicate ceramics. The presented results enable drawing up the conclusions concerning the resistance of investigated material to the ageing degradation process development during long term operation.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: Photoacoustic diagnostics of inhomogeneous gyrotropic materials with internal stress using Bessel light beams
Fotoakustyczna diagnostyka niejednorodnych żyroskopowych materiałów z wewnętrznymi naprężeniami z zastosowaniem laserowych wiązek Bessela
Autorzy:: Mityurich, G.
Aleksiejuk, M.
Ranachowski, P.
Pelivanov, I.
Serdyukov, A.
Tematy:: spektroskopia fotoakustyczna
laserowe wiązki Bessela
materiały żyroskopowe i magnetoaktywne
photoacoustic spectroscopy
Bessel light beams
magnetoactive gyrotropic materials; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/352967.pdf Link otwiera się w nowym oknie
Opis:: This paper considers the investigation of photoacoustic transformation in naturally-gyrotropic and magnetoactive crystals, with internal stress under sound excitation in different modes by Bessel light beams (BLB). In the range of high modulation frequencies (? > 1 MHz), the dependence of the photoacoustic response amplitude on the radial coordinate ? exhibits resonant phenomenon, which can be used to increase the resolution of photoacoustic spectroscopy for media with internal stresses. The expressions for amplitudes of photoacoustic signals in strained crystalline samples were obtained under different boundary conditions, taking into account the dependence of the thermoelastic coupling coefficient on the initial strain in the sample. It was showed that a resonant increase in the amplitude signal is related to the dependence on the geometric parameters of the sample-piezoelectric transducer system, the values of Murnagan constants, the mode composition of the Bessel light beam, and its amplitude modulation frequency.
W pracy przedstawiono wyniki badań transformacji fotoakustycznej poprzez dźwięk generowany laserowymi wiązkami Bessela o różnych modach w kryształach naturalnie żyrotropowych i magnetoaktywnych, z wewnętrznymi naprężeniami. Stwierdzono, że w zakresie modulacji o wysokiej czestotliwosci ( > 1 MHz), zależność amplitudy odpowiedzi fotoakustycznej od radialnej współrzędnej wykazuje efekt rezonansowy. Efekt ten może być wykorzystany do podwyższenia rozdzielczości spektroskopii fotoakustycznej w ośrodkach z wewnętrznymi naprężeniami. Otrzymano wyrażenia na amplitudy sygnałów fotoakustycznych w próbkach krystalicznych z wewnętrznymi naprężeniami, przy różnych warunkach brzegowych. Brano przy tym pod uwagę zalezność współczynnika sprzężenia termoplastycznego od wewnętrznych naprężeń w próbce. Wykazano, że rezonansowy wzrost amplitudy sygnału jest zależny od geometrycznych parametrów układu próbka – przetwornik piezoelektryczny, wartości stałych Murnagana, modów wiązki Bessela i częstotliwości modulacji.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: Study of factors determinant of siliceous electrical porcelain resistance to structural degradation
Autorzy:: Ranachowski, P.
Ranachowski, Z.
Kudela Jr., S.
Pawełek, A.
Piątkowski, A.
Tematy:: porcelain insulating materials
ageing processes
acoustic emission (AE)
optical microscopy; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/351813.pdf Link otwiera się w nowym oknie
Opis:: The subject of this study was investigation of the factors that have a decisive influence on the resistance of siliceous porcelain to degradation processes. There was tested material C 110 type, which is widely used for the production of low-voltage (LV) elements such as insulators and bushings. On the basis of mechanical-acoustic and microscopic research of small-sized samples, which were subjected to compression, there were distinguished successive stages of degradation of the material structure. In the authors* opinion, they have a reference to the ageing process, taking place during many years of work under operating conditions. Thus, it was possible to assess the structural factors that determine the durability and reliability of LV electroinsulating elements. The results were related to electrical aluminous porcelains.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: The Application of Acoustic Emission and Artificial Neural Networks in an Analysis of Kinetics in the Phase Transformation of Tool Steel During Austempering
Autorzy:: Łazarska, M.
Woźniak, T. Z.
Ranachowski, Z.
Ranachowski, P.
Trafarski, A.
Tematy:: carbon steel
austempering
lower bainite
acoustic emission (AE)
neural networks; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/352705.pdf Link otwiera się w nowym oknie
Opis:: During the course of the study it involved tool steel C105U was used. The steel was austempered at temperatures of 130°C, 160°C and 180°C respectively. Methods of acoustic emission (AE) were used to investigate the resulting effects associated with transformations and a large number of AE events were registered. Neural networks were applied to analyse these phenomena. In the tested signal, three groups of events were identified of: high, medium and low energy. The average spectral characteristics enabled the power of the signal spectrum to be determined. After completing the process, the results were compiled in the form of diagrams of the relationship of the AE incidence frequency as a function of time. Based on the results, it was found that in the austempering of tool steel, in the first stage of transformation midrib morphology is formed. Midrib is a twinned thin plate martensite. In the 2nd stage of transformation, the intensity of the generation of medium energy events indicates the occurrence of bainite initialised by martensite. The obtained graphic of AE characteristics of tool steel austempering allow conclusions to be drawn about the kinetics and the mechanism of this transformation.
Dostawca treści:: Biblioteka Nauki

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